Bus Engine into a 914

[ChrisG]

Well, I know - it is a mortal sin with the 914 and yes - I know there will possibly be a loss of power in the 914.

However I have a dilemma here which leaves me with a half firing engine and no replacement motor.
Start at the Beginning.
As many of you wont know, or maybe I am wrong, but the 914 is not exactly a popular car in the UK - last count was at less than 100 cars on the road and just under 200 registered in the country (of which quite a few will have been scrapped).
Now, with only the Porsche Club of GB out there for connection and a dubious underground of 914 parts "dealers" there is nearly no way you will ever find any replacement parts without breaking your back or buying a whole imported car from the USA, butchering it and then trying to sell it on.

Now the 1.7 I have in at the moment is in a pretty poor condition - the FI is quitely dieing, No.3 Cylinder is at 40 PSI and getting lower, the engine keeps making unwholesome noises and very soon it will enter the big engine grave yard in the sky.

Personally I want to get hold of a 2.0l replacement, have it rebuilt professionally and exchange the engine for the old one in the car.
Simple idea - except for the fact that there are no such engines over here, or at least not that I can find!

Now pretty much, I have to find a replacement and I have three options
1/ take out the 1.7, send it off for a rebuild and stainless valves (as the UK law means we wont be able to buy leaded fuel at the end of the year!), get a carb kit and put it back in
Drawbacks though are its going to take over 6 weeks for this to happen (which leaves me without the car) and it could cost upwards of $5000 (£3000 over here)
2/ I get hold of a second hand 911 motor (2.4T engine with carbs), get the conversion kit for the 914 and pray to god that it wont cost more that $5000 - Extra BHP but at a cost and time - estimated at 3 months off the road!
3/ Go down to the local scrap yard, rip and 2.0l type 4 engine out of a late model bus,
send it off to Volkspares who then send me back the engine within a week (no - it will be a replacement and not that engine). Buy a carb kit for the engine, fit it, electronic ignition it and put it in. The Engine is fully rebuilt with new parts and it comes with a years guarantee.
Total cost would be less that $3000 or £2000

The real question here is - how compatible is the Type 4 Bus engine to the 914?
I know through playing with the engine before in VW Beetles that the filler is different, however I need to know if the exhaust is different, the mounting points are differnet, if the clutch and Flywheel is different etc etc.

I am really out of options here.
If anyone can offer any advise at all I would be extremely grateful

[JP Noonan]

Kind of short on time right now, but I'll try to skim over it for you.

Option Four: In the states anyway new big bore pistons and liners for a 1.7L are $150-$165. The bottom end could be left alone, but it probably needs to be rebuilt.

Take of the heads and see if the compression loss is from a burnt valve. If that's the case just put some good used 1.7L heads on. 914 and VW 1.7L heads I think are all the same. This may be your cheapest/best route because you're not investing a lot of time and money into a worn out block.

Look around the past postings, I've discussed the many differences between 914 and bus blocks. At the very least get a pre 80 block (the 80-83 have a cast over oil filler and rectangular exhaust ports). Aslo look closely at the oil dipstick/filler area. On my 78 bus engine it looked like it would hit the engine mount bar. The flywheels are different, and later buses had hydro lifters.

Ask the place rebuilding the motor how much extra to put in a different (914 specific) cam if they are putting in a new cam anyway. Also ask if higher compression pistons can be used and how much. About the unleaded, as far as I know ALL aluminium head VW motors have cast iron valve seats, so thet ALL work with unleaded, just use the highest octane you can, or if it still knocks retard the timing a little.

[ChrisG]

Thanks for the advice.

Looking back on it now - I think that having the 1.7 refitted is the best option.

John Maher Racing is the company where I am considering having the engine refitted and to be honest even though the cost is a little higher than normal the spec he will deliver is good.
The crank and case will be reground - the crank will also be balenced.
The heads get a complete workover - new seats, stems, valves etc. Any cracks are also welded up and repaired.
The Barrels and Pistons are brand new.

Also I will, with all luck be fitting a G Grind cam to the engine to compensate for the changes in the FI balenced stock cam when converting over to carbs.

I too have heard that Unleaded fuel is the norm in VW engines, however when pinned down nobody I know will admit it.
VW Trends and Volksworld in the UK say something along the lines of "for every 3 fill ups of unleaded add one of leaded."

However, it seems odd that the companies over here are now heavily plugging unleaded heads and conversion kits for both VW's and 914's.

Actually remembering my old Type 4 engine, the later van units also have the fuel pump mounted to the side of the engine, at the back under the tinwear.

I think that is my mind made up - I will go for the 1.7 rebuild.

Thanks again for the advice.

[JP Noonan]

The fuel pump you descibe is probably the mechanical type that ran off the cam. Some companies make block off plates, that's the least of the problems.

To my knowledge in "leaded" fuel (has a trichloral-something-or-another) the "lead" is for the soul purpose of reducing "valve seat resesion". VSR happens when the vavle becomes so hot it erodes part of the vavle seat off the heat every time it contacts it. The lead acts as a buffer, to transfer the heat from the vavle into the heat before the vavle gets too hot. I've been told (actually by a British mag, Porsche 911) that you can get away with alternating tankfuls because of a "residual" amount of lead on the seats. Also if you drive the car at light load VSR won't happen. Leaded vs. unleaded and octane ratings are one of those things that everyone (including me) thinks they know about because of what or uncle told them when they were young or what some "expert" friend knows. Add to this all those machine shops that won't "lie", but would love to have everyone think their heads need a retro-fit. Anything can be twisted to make sense, but if you have the time read the gasoline article on this site. The big advantage leaded gas gives to 914 engines is that it is an easy/cheap way to raise octane. This may be why those one arm writers at VW trends say to use leaded. The other thing is your (any country other than the US or Canada) octane rating is different than ours, yours is artificially high. Something to the order of: 93 ron/mon (U.S. spec) is roughly equal to your 95-96 octane.

Personally I use 92-93 octane in both my 72 1.7L (requires 98 oct acording to owners manual, but octane ratings have changed since 72) and my low (U.S. spec) compression 75 2.0L, with no detonation or overheating.

I think you are making the right choice. It sounds easy, but putting a bus motor in a 914 isn't all it's cracked up to be.

[Alpine]

The book

How to Rebuild Your Volkswagen Air-Cooled Engine by Tom Wilson, ISBN: 0-89586-225-5

is an excellent source of information on how to rebuild all of the air-cooled VW engines including the 914 engines. It also explains in detail the differences between the various engines.

Alpine